When I was little, geologists worked out Earth's surface was made of pieces, like a giant puzzle. Those pieces, called “tectonic plates”, move and bump into each other and mountains form.

The United Nations says people “left behind” include those vulnerable to the effects of climate change, but aren’t the furthest behind those damaging the environment? Here, a man rides a bicycle through a devastated Homs, Syria. Numerous studies say climate change was a factor in record-setting drought, one of several causes of the country’s civil war.
AP Photo/Dusan Vranic
Desember 11, 2018

A solar day is a measure of how long it takes the Earth to rotate from one noon to the next, and today's summer solstice also happens to be the longest solar day of the year.

The mass of the Earth is big enough that the gravitational force it creates can pull the hard shape of ice, rock and metal into a sphere.
NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center
September 19, 2017

Imagine the Earth pulling everything it is made up of, all of its mass, towards its centre. This happens evenly all over the Earth, causing it to take on a round shape.

Lasers being shone from the European Southern Observatory’s Very Large Telescope in Chile.
These lasers help remove the twinkles in the night sky and help astronomers see stars clearer on Earth than ever before.
F. Kamphues/ESO
September 3, 2017